Biology subjects

Rowitch, D. H.

Publications and source records attributed to Rowitch, D. H..

9 recordsLinked to original sources

bioRxiv2026

SpiraMed: A Stereotactic Helix-based Therapy Delivery system for the Human Brain

Stereotactic needle-based delivery remains the standard for local administration of Advanced Therapy Medicinal Products (ATMPs) to the human brain. ATMP administration typically involves multiple trajectories, presenting cumulative risks and prolonging surgery. Reflux-prone, patchy therapy coverage compromises clinical results. We demonstrate a novel approach, deploying a helical delivery catheter via a single access trajectory per target, referred to as SpiraMed. Helix retraction is synchronised with therapy delivery, enabling comprehensive target coverage in seconds. Helix pitch and diameter can be precisely tailored to patient-specific target volume and vascular anatomy, as part of the preoperative stereotactic surgical planning process. Testing in agarose phantoms, live sheep and cadaveric human brain confirms enhanced therapy delivery volume, delivery speed and target coverage, with reductions in reflux and predicted risk of bleeding complication. SpiraMed represents a new paradigm, promising to help deliver on the transformative potential of cell and gene therapies across the spectrum of human CNS disease.

bioengineering↗

bioRxiv2026

Myelin basic protein is an RNA chaperone in microglial nuclear retro-transport

CNS oligodendrocytes generate myelin, an RNA-containing proteolipid substance that enhances axonal transmission. In multiple sclerosis (MS), myelin debris is phagocytosed by microglia (MG), and prior studies have detected myelin-derived mRNA in MG nuclei, suggesting a retrograde transport pathway. We report myelin basic protein (MBP) is a nucleic acid-binding and trafficking protein. We found that retro-transport of myelin RNA into the MG nucleus was phagocytosis and importin-dependent. Transcriptomic and proteomic analyses of MG nuclei revealed enrichment of myelin mRNAs and proteins, with MBP singularly detected in soluble and chromatin-associated fractions. MBP bound mRNA with high affinity (Kd {approx} 0.30 nM) and was sufficient to facilitate MG RNA nuclear import in vitro and in vivo. Functionally, MBP mediated the delivery of small interfering RNAs for targeted knockdown of toll-like receptor 4. These findings indicate MBP as an RNA-binding protein capable of MG nuclear import, providing insight into neuroinflammatory pathology of MS.

neuroscience↗

bioRxiv2025

A spatiotemporal cancer cell trajectory underlies glioblastoma heterogeneity

Cancer cells display highly heterogeneous and plastic states in glioblastoma, an incurable brain tumour. However, how these malignant states arise and whether they follow defined cellular trajectories across tumours is poorly understood. Here, we generated a deep single cell and spatial multi-omic atlas of human glioblastoma that pairs transcriptomic, epigenomic and genomic profiling of 12 tumours across multiple regions. We identify that glioblastoma heterogeneity is driven by spatially-patterned transitions of cancer cells from developmental-like states towards those defined by a glial injury response and hypoxia. This cellular trajectory regionalises tumours into distinct tissue niches and manifests in a molecularly conserved manner across tumours as well as genetically distinct tumour subclones. Moreover, using a new deep learning framework to map cancer cell states jointly with clones in situ, we show that tumour subclones are finely spatially intermixed through glioblastoma tissue niches. Finally, we show that this cancer cell trajectory is intimately linked to myeloid heterogeneity and unfolds across regionalised myeloid signalling environments. Our findings define a stereotyped trajectory of cancer cells in glioblastoma and unify glioblastoma tumour heterogeneity into a tractable cellular and tissue framework.

cancer biology↗

bioRxiv2023

The Neonatal Gyrencephalic Cortex Maintains Regionally Distinct Streams of Neuroblasts

Neurodevelopmental mechanisms have evolved to support the formation of diverse brain structures, such as in humans, during the perinatal period. Here, we demonstrate that neonatal gyrencephalic brains harbor an expanded subventricular zone, termed the Arc, defined by tiered arrangement of doublecortin (DCX)-expressing neuroblasts and vascular enrichment at the ventricular wall. The Arc is the origin of dorsal and ventral populations of migratory neuroblasts that target multiple regions involved in higher cognitive functions. Arc-derived migratory streams, primarily from the caudal ganglionic eminence, are composed of diverse neuronal subtypes with distinct spatial and migratory-receptor profiles. Our findings indicate the Arc is a structure present in phylogenetically divergent species that supports the expansion of postnatal neuronal migration, contributing to a protracted formation of cortical circuits in gyrencephalic brains. One-Sentence SummaryThe ventricular cytoarchitecture of gyrencephalic brains supports an ongoing supply of migratory neurons to the neonatal cortex.

neuroscience↗

bioRxiv2022

A retroviral origin of vertebrate myelin

Myelin, the insulating sheath that surrounds neuronal axons, is produced by oligodendrocytes in the central nervous system (CNS). This evolutionary innovation, which first appears in jawed vertebrates, enabled rapid transmission of nerve impulses, more complex brains and greater morphological diversity. Here we report that RNA level expression of RNLTR12-int, a retrotransposon of retroviral origin, is essential for myelination. We show RNLTR12-int-encoded non-coding RNA binds to the transcription factor SOX10 to regulate transcription of myelin basic protein (Mbp, the major constituent of myelin) in rodents. RNLTR12-int like sequences (which we name RetroMyelin) are found in all jawed-vertebrates and we further demonstrate their function in regulating myelination in two different vertebrate phyla (zebrafish and frogs). Our study therefore suggests that retroviral endogenization was a key step in the emergence of vertebrate myelin.

neuroscience↗

bioRxiv2021

Evidence for glutamine synthetase function in mouse spinal cord oligodendrocytes

Glutamine synthetase (GS) is a key enzyme that metabolizes glutamate into glutamine. While GS is expressed by astrocytes of the central nervous system (CNS), expression in other glial lineages has been noted. Using a combination of reporter mice and cell typespecific markers, we show that GS is expressed in myelinating oligodendrocytes (OL) but not oligodendrocyte progenitor cells (OPC) of the mouse spinal cord abutting ventral horn motor neurons. To investigate the role of GS in mature OL, we used a conditional knockout (cKO) approach to selectively delete GS-encoding gene (Glul) in OL, which caused a significant decrease in glutamine levels on spinal cord extracts. We evaluated the effect on ventral spinal cord sensorimotor circuits and observed that GS cKO mice (CNP-cre+: Glulfl/fl) showed no differences in motor neuron numbers, size or axon density; OL differentiation and myelination in the ventral spinal cord at 1- and 6-months of age was normal. Interestingly, GS cKO mice showed an early and specific decrease in peak force while motor function remained otherwise unaffected. These findings provide evidence OL-encoded GS functions in spinal cord sensorimotor circuit. Main pointsO_LIGlutamine synthetase (GS) is highly expressed in oligodendrocytes (OL) of the mouse spinal cord. C_LIO_LIOL-specific GS loss of function causes transient decrease in peak force, but other substantial neurological dysfunction was not detected. C_LI

neuroscience↗

bioRxiv2021

The neuroprotective effects of Sonic hedgehog pathway agonist SAG in a rat model of neonatal stroke

ObjectiveNeonatal stroke affects 1 in 2800 live births and is a major cause of neurological injury. The Sonic Hedgehog (Shh) signaling pathway is critical for central nervous system (CNS) development and has neuroprotective and reparative effects in different CNS injury models. Previous studies have demonstrated beneficial effects of small molecule Shh-Smoothened-agonist (SAG) against neonatal cerebellar injury and it improves Down syndrome-related brain structural deficits in mice. Here, we investigated SAG neuroprotection in rat models of neonatal ischemia-reperfusion (stroke) and adult focal white matter injury. MethodsWe used transient middle cerebral artery occlusion at P10 and ethidium bromide injection in adult rats to induce damage. Following surgery and SAG or vehicle treatment we analyzed tissue loss, cell proliferation and fate, and behavioral outcome. ResultsWe report that a single dose of SAG administered following neonatal stroke preserved brain volume, reduced inflammation, enhanced oligodendrocyte progenitor cell (OPC) and EC proliferation, and resulted in long-term cognitive improvement. Single-dose SAG also promoted proliferation of OPCs following focal demyelination in the adult rat. ConclusionThese findings indicate benefit of one-time SAG treatment post-insult in reducing brain injury and improving behavioral outcome after experimental neonatal stroke.

neuroscience↗

bioRxiv2019

Nutritional signals rapidly activate oligodendrocyte differentiation in the adult hypothalamic median eminence

The mediobasal hypothalamus (arcuate nucleus - ARC - and median eminence - ME -) controls energy balance, growth and fertility through its ability to integrate neuronal, nutritional and hormonal signals and coordinate the behavioural, neuroendocrine and metabolic responses required for these functions. While our understanding of the neural circuits downstream from ARC neurons is rapidly progressing, little is known about the function of other cell types. Here we describe an unexpected role for oligodendrocytes (OL) of the ME in monitoring nutritional signals. We show that refeeding following an overnight fast rapidly activates oligodendrocyte differentiation and the production of new OL in the ME specifically. No changes in myelination were measured in this time-frame. However, refeeding changed the expression of OL-derived extracellular matrix proteins decorin and tenascin-R, with consistent changes in the density of local perineuronal nets. Last, we show that OLs use mTORC1 signalling, a pathway required for OL differentiation, to survey energy and protein availability, specifically in the ME. We conclude that new oligodendrocytes formed in the ME in response to nutritional signals control the access of circulating metabolic cues to ARC interoceptive neurons.

neuroscience↗

bioRxiv2018

Single-cell in situ transcriptomic map of astrocyte cortical layer diversity

During organogenesis, patterns and gradients of gene expression underlie organization and diversified cell specification to generate complex tissue architecture. While the cerebral cortex is organized into six excitatory neuronal layers, it is unclear whether glial cells are diversified to mimic neuronal laminae or show distinct layering. To determine the molecular architecture of the mammalian cortex, we developed a high content pipeline that can quantify single-cell gene expression in situ. The Large-area Spatial Transcriptomic (LaST) map confirmed expected cortical neuron layer organization and also revealed a novel neuronal identity signature. Screening 46 candidate genes for astrocyte diversity across the cortex, we identified grey matter superficial, mid and deep astrocyte identities in gradient layer patterns that were distinct from neurons. Astrocyte layers formed in early postnatal cortex and mostly persisted in adult mouse and human cortex. Mutations that shifted neuronal post-mitotic identity or organization were sufficient to alter glial layering, indicating an instructive role for neuronal cues. In normal mouse cortex, astrocyte layer patterns showed area diversity between functionally distinct cortical regions. These findings indicate that excitatory neurons and astrocytes cells are organized into distinct lineage-associated laminae, which give rise to higher order neuroglial complexity of cortical architecture.

neuroscience↗